Because transitioning to fully renewables takes a LOT of overbuilding, and by that point we will have taken all the lowlying fruit.

As an example, in BC, we recently completed the Site C dam, which was considered an ok, if not ideal, location for a dam. Now to meet BC's growing energy demands, they are investigating the Site E location .

When the utility applied to the B.C. Utilities Commissions to build Site C in 1980, it said Site E "would have required major relocations, flooded considerably more farmland, resulted in extensive instability of the reservoir banks … and had a considerable effect on development in the Taylor area."

The fact that we are digging up a highly problematic, previously rejected project shows we are running out of viable locations for clean hydro in BC. Because of this, people are already pushing for Natural Gas generation to back things up, which defeats the purpose of a clean transition.

Furthermore, switching completely to renewables and utility-scale batteries shifts the bottleneck from building reactors to digging mines & building factories. To overbuild that much infrastructure requires an astronomical amount of copper, lithium, and rare earth metals. Spinning up a single new large-scale mine from exploration to production takes 10 to 15 years due to regulatory and engineering hurdles.

Neither option is a quick fix. But if both paths require a multi-decade timeline, why not diversify into something Canada has a lot of, and is carbon neutral: nuclear.